San Diego 
Federal officials said 80 to 90 percent of the U.S. citizens re-entering the United States by land were carrying a passport or other secure document Monday morning, the first day of new travel regulations requiring passports, a passport card, a SENTRI pass or similar trusted traveler document to reenter the country by land or sea.

Border waits at 7 a.m. at the San Ysidro port of entry were a little over an hour, which isn't unusual for a Monday morning, when both U.S. and Mexican citizens who live in Baja California commute north to jobs in San Diego County.

Waiting in line in a minivan with her stepfather and her four children, Mariana Perez of Imperial Beach carried her passport, along with a file folder containing passport receipts and birth certificates for her kids.

“These are OK, right?” asked Perez, 32, who said she had spent the weekend in Tijuana helping her ailing mother and was on her way north to a doctor's appointment in San Diego for one of the children.

Tijuana resident Maria Teresa Acosta, 67, carried a passport card as she drove to work in San Diego, where she works for a seniors' program. She'd been expecting a long wait in line, but said the wait was nothing out of the ordinary.

“It's gone fast,” she said. “Sometimes I'm here for two hours.”

The change is part of what is called the Western Hemisphere Travel Initiative, an outgrowth of national security legislation enacted five years ago.

Passports have been required for air travelers returning from within the region since January 2007.

As of Monday, when returning through land or sea ports of entry from Mexico, Canada, Bermuda and the Caribbean, U.S. citizens are now required to present a passport or one of a handful of accepted documents: a passport card, a “trusted traveler” card such as a SENTRI pass, or a driver's license enhanced with radio-frequency technology, issued in some states but not California.

U.S. citizens carrying receipts proving they have applied for a passport are being allowed in.

The waits at the border eased as the morning went on, which is also typical. At 11 a.m., there was a 30-minute delay at San Ysidro, with 20 lanes open, according to Customs and Border Protection officials, and a 15-minute delay as of 10 a.m. at the Otay Mesa border crossing.